Sharkey S W, Murakami M M, Smith S A, Apple F S
Cardiology Division, Hennepin County Medical Center, Minneapolis, Minn. 55415.
Circulation. 1991 Jul;84(1):333-40. doi: 10.1161/01.cir.84.1.333.
Creatine kinase (CK) exists as three cytosolic isoenzymes, CK-MM, CK-MB, and CK-BB, and one mitochondrial isoenzyme. Animal and human observations suggest that the CK-MB content of myocardium is dynamic and may increase in response to ischemia, but the response of the myocardial CK system to chronic coronary artery occlusion is not well-defined.
We measured serial changes in myocardial total CK, percent CK-MB, and percent CK-BB before and 3 weeks after coronary artery occlusion in 17 pentobarbital-anesthetized dogs. Tissue biopsies were obtained from the left anterior descending (LAD) coronary artery myocardium, the right coronary artery (RCA) myocardium, and the circumflex coronary artery myocardium at baseline and 3 weeks after LAD occlusion (n = 6), RCA occlusion (n = 5), and no coronary artery occlusion (n = 6). Tissue samples were assayed for total CK, percent CK-MB, and percent CK-BB. Samples were also examined by electron microscopy for evidence of ischemic myopathy. Total myocardial CK activity did not change over 3 weeks. Percent CK-MB increased significantly in the tissue supplied by the occluded artery (4.1-fold in dogs with LAD occlusion and 6.7-fold in dogs with RCA occlusion). Percent CK-BB did not change. Dogs with LAD occlusion had ultrastructural evidence of myopathic fibers interspersed with normal fibers in the LAD myocardium. Dogs with RCA occlusion had no ultrastructural evidence of myopathic fibers in the RCA myocardium.
Chronic coronary artery occlusion causes a pronounced change in the canine myocardial CK system that is limited to the tissue supplied by the occluded coronary artery. These biochemical alterations do not correlate with any cellular ultrastructural changes. Myocardial CK-MB content is dynamic, varies geographically within the heart, and increases rapidly after coronary artery occlusion.
肌酸激酶（CK）以三种胞质同工酶即CK-MM、CK-MB和CK-BB以及一种线粒体同工酶的形式存在。动物和人体观察表明，心肌中的CK-MB含量是动态的，可能会因缺血而增加，但心肌CK系统对慢性冠状动脉闭塞的反应尚不明确。
我们在17只戊巴比妥麻醉的犬中，测量了冠状动脉闭塞前及闭塞后3周心肌总CK、CK-MB百分比和CK-BB百分比的系列变化。在基线时以及左前降支（LAD）闭塞（n = 6）、右冠状动脉（RCA）闭塞（n = 5）和无冠状动脉闭塞（n = 6）后3周，从LAD冠状动脉心肌、RCA冠状动脉心肌和回旋支冠状动脉心肌获取组织活检样本。对组织样本进行总CK、CK-MB百分比和CK-BB百分比检测。样本还通过电子显微镜检查有无缺血性肌病的证据。心肌总CK活性在3周内未发生变化。闭塞动脉供血的组织中CK-MB百分比显著增加（LAD闭塞的犬增加4.1倍，RCA闭塞的犬增加6.7倍）。CK-BB百分比未发生变化。LAD闭塞的犬在LAD心肌中有肌病性纤维与正常纤维相间的超微结构证据。RCA闭塞的犬在RCA心肌中无肌病性纤维的超微结构证据。
慢性冠状动脉闭塞导致犬心肌CK系统发生显著变化，且仅限于闭塞冠状动脉供血的组织。这些生化改变与任何细胞超微结构变化均无关联。心肌CK-MB含量是动态的，在心脏内各部位有所不同，且在冠状动脉闭塞后迅速增加。
